Tube cleaning head



Patented Dec. 26 1944 'UNITED STATES EATENTQFFIVCEY f TUBE CLEANING-HEADMorril B. Spaulding Habana, Cuba ,Applicationlv farch 27, 1942, SerialNo. 436,503

3 Claims. (C1.15--104.09)

The present invention relates to improvements in tube cleaning heads forremoving scaleand other incrustations from the inner surfaces of thetubes ofboilers, heaters, condensers, evaporators and similar apparatus,and it is more particularly applicable to the cleaning of tubes whichare composed of relatively soft metal, such as copper or bronze. i

The primary object of the invention is to provide a novel and improvedtube cleaning head which is capable not only of removing rapidly andefficiently relatively hard and dense scale or incrustations from theinterior surfaces of relatively soft metal tubes but is capable of doingso Without shaving, striating or otherwise damaging the metal and ofimparting a burnished finish to the interior surface of the tube, sothat no pits or other irregularitieswill be leftin the metal surface ofthe. tube to promote the subsequent accumulation of scale or otherdeposits thereon.

Tube cleaning heads having radial blades pressed outwardly to engage theinner'walls of tubes and effect a cleaning action by rotation of thehead have been previously proposed, but such heads have not provenentirely satisfactory. In such previously proposed heads of this typewhich I am aware of, no means has been provided for centering the headin th tube or gauging the extent of outward movement of the blades, so

that the blades had a tendency to exert undue pressure at one side ofthe tube,and of shaving,

striating, and otherwise damaging themetal of the tube, especially whenthe tube is composed of copper or similar relatively soft metal.

i The present invention provides animproved cleaning head of this typewhich overcomes these objections and produces novel and improvedresults. According to the present invention, the head is provided withmembers which serve to center the head in the tube and to control theaction of' the blades, whereby the blades are caused to act on theinnersurface of thetube uniformly around its circumference, thus effectingthorough cleaning of the tube without undue pressure against anyone sideof the tube, such as would shave the metal therefrom, and the cuttingedgesof the blades are maintained par:

allel to thetube walls, thus insuring efficient action of the bladesthroughout their lengths and avoiding striating the metal of the tube,and by controlling the action of the blades and centering them withinthe tube, a burnishing action is produced on the inner tube surfacewhich closes the pores of the metal and producesa smoothsur-Q face whichminimizes adhesion of scale or other deposits thereon.

The preferred embodiment of the invention is shown in theaccompanyingdrawing wherein Figure 1 is a side elevation of the improved tubecleaning head; i i i Figure 2 is a central longitudinal section thereof;i Figure 3 is a transverse section taken on the line 33 in Fig.2; and iFigure 4 is a view of the body of the head wit the blades removed.Similar parts are designated by the same refer. ence characters inthedifferent figures. i

The improved tube cleaning head, in its preferred'construction,comprises a body I which is in the form of a solid cylinder having asuitable number, at least three, of radial slots 2 formed therein, fourof these slots being shownin the present instance. These, slots extendin parallelism to the central or longitudinal axis of the head and arespaced equidistantly circumferentially thereof. A blade 3 is fittedloosely in each of these slots, these blades being freely movableradially intheir slots, the outer edge, of each blade being bevelled toprovide a relatively sharp scraping or cleaning edge 4 extendingthroughout its length. The body of the head and theblades are composedofappropriate metal, and the body i may varyin diameter and length, andthe blades may vary in length, radial width and thickness according tothe inside diameters of the different 6 which is threaded removably on ascrew-threaded stem 1 which projects axially from one end of the headand has an annular counter-bore 8 formed therein'toreceive theextensions 5 on the bladesadjacent to one end of the head, and a collar9 which is threaded removably on a screwthreaded shank In which extendsaxially from the other end of thehead, said collar having an annularcounter-bore II to receive the extensions 5 on theblades adjacent tothat end of the head.

The blades maybe inserted into or removed from their slots while one orboth the disk 6 and collar 9 are unscrewed or removed, and when theseparts are screwed into their places, as shown in Fig. 2,

"55, they permit radialmovements of the blades in their slots but limittheir outward movement and prevent displacement from their slots underthe centrifugal force developed in the blades by the rotation of thehead.

According to the present invention, the head the disk I2 having a sleevel3 thereon which is internally threaded to screw onto the threaded shankIll and abut against the collar 9 to lockit in place and provide adriving connectionfor the head, this disk l2 having a, screw-threadedstem outwardly with a force of the proper magnitude to effectivelyscrape and remove the scale or incrustation from the tube during theadvance of the head through the tube, and during the retractionor'withdrawal of the head from the tube, the blades produce a burnishingaction upon the inside surface of the tube, which closes the pores inthe metal and provides it with a smooth finish devoid of pits in whichscale forming substances might lodge, thus delaying the subsequentaccumulation of scale oriincrustati'on; Each use of the head renders theinside surface of the tube denser, thus reducing the tendency of scaleto adhere thereto.

As thedisks on the head maintain the outer scraping edges of the bladesin parallelism with the'inside wall of thetube, maximum scraping l4projecting therefrom for theattachiment .of.a

universal joint I5 which may be connected to a rotary steam or air motorfor rotating "the cleaning head at an appropriatespeed. a

The disks 6 and IZ-are each of generally, circular form andxofasdiam'eter, about-p s of. an inch less than .theinside diameter of. thetube -to be cleaned, such as the tubewdesignatedX in Figs. 2 and 3,andthe depth of the slots 2 andthezradial width of theblades 3 are soproportioned: that the diameter of said disks is greater than :that ofthe-circle in which the outer edges of thezbla'des lie when the bladesare retracted to their inner most positions, or rest against :the innerends of their radial slots. This feature oithepresent invention preventsassolid bearingwoffthesblades against any one :side of the tube :being.cleaned,

since each blade can move .into its.:s10t so that its outer edge iswithin theperiph'eries of the disks at the respective sides thereof,although all of the blades will float in a circle, the diam'eteriofwhich is greater than that of thediskst-fiandufl. Asithese disks areof"a diameternearlyequalIto 'thevinsi'de diameter of: the tubebeingcleaned, theywill center the'headin the tub'elwith'its axis parallel tothat 'of;the"tube,' sosthattheiouter bevelled edges of theiblades willbe held: parallel to-the inside wall of the tubexandswilltherefore actthereon uniformly throughout theinlength. The peripheries- 0f theidiskswlian'dil ZJaTe provided with" circumferentially spaced recesseswl fisand 11 respectively to afford free'vpassagewaysi'through whichairiexhausted from-,athe ainmotor may 'ilo'w past the head and thusfcarry away the: particles of scale or. incrustation removed "from? thetube by the cleaning head, as whenitheuhead isxemployed'for dryycleaning:of'tubes EOr'fOI- thBflOW- of liquid which will-wash: :awayFsuchiparti'cl'es when the head is' employedwforrwet cleaning Y1 Theprojections I a and I 9-intervening :lther' recesses provide amplebearing;surfacesziforthe smooth -rota tion'of the-head in thei-tube.

In iusingga xcleaning head' constructed asihere inbefore described,aiahead rofra:sizeoappropriate for the inside diameter 'offthe tuber-tobe cleaned islcon'nectedby thesuniversalL-joint l5-'-=to an air motororother' suitable :operatin'g meansand- 'in serted into one-end ofithe'itube and driven at a speed of preferably about 6500 revolutions perminute. -Whilel therhead, lissb'einga of-driven; it is advanced to Y theother :end. ofith e ube,..the'- head removing the'sscale .orincrustati'on as itfadvan'ces,

after which the head isrwithdrawnifrom tlre tube.

Y virtue *of' the :freedom f:radialnmovement of the blades inithei-rslots,- theyareufcrced outwardly= by thescentrifug-alforce rde-veloped:by the high speed; rotation. or thecrheadgi theeouter' b'ev elled: edgesof the: blades 'being itherebyzpressed capacity is attainedby theutilization of the entire length of the blades, which also minimizes'the rateof wear of the blades, and furthermore,

the ends :of the bladescannot gou e into the metal and thus score,striate or'otherwisedamagelthe tube.-

Although tube cleaning heads constructedxin accordance with the presentinvention mayibe similar apparatus, they are especially adapted to meetthe requirements in the cleaning of the copper tubes of evaporators orotherapparatus employedin sugar manufacture-in which'the de-' positsareof 'a ceramic nature and are hard and dense theimproved cleaning headenabling such scaleor incrustationto be: removed rapidly 'and withoutdamaginglthe relatively soft metal composing the tubes, andimparting totheltubes a burnished or polished surface which inhibits the subsequentaccumulation 'of scale. or incrustation.

'Since thepressure of the blades against the inside 'oi'the tube duringthe operation'zofi'the cleaning, head, is produced solelyby=thelcentriiugal -=force developed in :the: blades by the rotation ofthe: head, and the action of .the' blades ion :the tube is controlled bythe disks the :structur'euof the head-is notion-1y simple-but ethe-:pressurevex erted by, all, of the: blades is equal, and liftingaorshaving; of the metal-0f theltu-be is @ayoidedgand moreover,themagni-tudezof pressureof thezblades against the inside ottheutube inorder to best meetdifferent requirements accordingqto dif- 'fe'rentnatures ofv the scale orincrustation tov be removed, and ..to. effectthe: burnishi-nggofl themside wall of the .tube, and .to. attain themaximum capacity, may be/readily variedby,appropriately varying'thespeedof rotationuof the-head during the cleaning and burnishingloperation. As the body, and "disks and "the, arrangement .of the-slotsfor the blades- "of'th'e head. aresymmetrical, these parts'ofthe head"are balanced dynamicallyland as the blades are heldby, centrifugalfbrceagainst the inner surface of the tube beingfclaneddthere is" noobiectidnabl vibration .'during 4 the operation oftheclean'inghead. V

realmas my'invention':

1; A rotatable tube"cleaninghead.comprisingca solid substantiallycylindrical body, 1 having threaded axial extensions, projecting, ramits ends and I formed with' 'radi'a'l circumferentially spaced "axiallyextending 'slots theinner ends of which areclosed, aset-nfbalancedblades freely movable radiaHy in said slots solely by centrifu gal forceduring rotation of "the head to "produce the pressure for removal ofincrustations on-the inner-surface of the tubebe'ing cleaned ander-m:ited: in their inward radial movement by *the closed inner ends of theslots, said blades having straightbevelled outer edges which extend;longitudinally of the head, and concentric centering disks rigidly fixedon the respective axial extensions projecting from the ends of the bodyandengageable bythe ends of the blades to limit outward radial movementthereof and to maintain the outer edges of the blades in substantialparallelism with the axis of the head, said disks and the inner ends ofthe slots providing fixed abutments whereby the outer edges of theblades may lie ininner and outer circles, andsaid disks being of adiameter greater than the inner but less than the outer circle andengageable with the inner surface of a tube being cleaned to center thehead therein and maintain the outer edges of the blades in parallelismwith said tube surface and to confine rotation of the outer edgesof theblades to paths between said inner and outer circles, said disks havingcircumferentially spaced recesses in their peripheries for the passageof fluid.

2. A rotatable tube cleaning head comprising a cylindrical body, aplurality of blades symmetrically spaced circumferentially and freelymovable radially between innerand outer fixed abutments, said bladeshavingbevelled outer longitudinal edges, and centering disks on the endsof the head concentric with said body and having circumferentiallyspacedprojections on theirperipheries for engagement with the inner surface ofa tubeto be cleaned, and having recesses; between said projections forthepassage of fluid,

said body and disks'being dynamically balanced. 3. A rotatable tubecleaning head comprising a solid cylindrical body having threaded axialex-v tensions projecting from its ends and formed with radialcircumferentially spaced axially extending slots closed at their innerends, blades movableradially in said .slots and having bevelledlongitudinal outer edges, a centering disk of greater diameter than saidbody threaded on one 1 of said axial extensions and cooperative withadjacent ends of the blades to limit their outward radial movement, asleeve threaded on the other of said axial extensions and cooperativewith the other ends of the blades to limit their outward radialmovement, and a second centering disk of greater diameter than said bodythreaded on said other axial extension in locking engagement with saidsleeve said disks being of a diameter to maintainthe outer bevellededges of the blades in parallelism with the inner surface of a tube tobe cleaned and to limit the outward radial movement of the blades towardsaid surface of the tube.

MORRIL B. SPAULDING.

